AU747116B2 - In-field sugar cane processor - Google Patents

Description

AUSTRALIA

Patents Act 1990 Trevor Essex Cuflinger

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 0e 0 0 0S 0@ 0* 0 *0 0 0 0 00 0 0 0000 Invention Title: 000 0 0 @0 0 0000 0 0 00 0 00 0 000 In -field sugar cane processor 060 The following statement is a full description of this invention including the best method of performing it known to us:- 6

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0 S50 Field of the Invention This invention relates to in-field processing equipment and in particular but not limited to an in-field processing machine for the processing of sugar cane for the purpose of extracting sugar cane juice.

The apparatus can be used in the production of raw sugar, or even the separation of the sugar components from the juice, for example, to sugar crystal and molasses. In one design the invention relates to the production of sugar cane juice, in another design the invention extends the processing to raw sugar, in another design the invention extends to separating the raw sugar crystals into brown sugars and molasses. This invention also relates to a method or process of extracting or separating either individually or in combination each separate component of the sugar cane from the sugar cane juice.

Background to the Invention 15 Although the invention to be discussed below relates to the principle of processing of sugar cane in the field, the invention could also be modified to facilitate the in-field processing of many other juicable products, and the other constituent components from sugar cane and for example, sugar beet or other sugar/saccharin containing bamboos, grasses or vegetables.

20 The sugar cane industry is an important agricultural industry which is a large export earner for Australia. Currently, Australian farmers produce in excess of 37 million tonnes of sugar cane annually, resulting in the production of approximately 5 million tonnes of raw sugar per annum.

Approximately 70% of the sugar produced in Australia is exported overseas.

25 Technologically, the industry is recognised as a world leader. A large amount of money is spent annually on research and development in the three principal areas of farming, milling, and marketing.

Although the industry is well placed, competition from subsidised overseas production and emerging Third World producers, combined with 30 fluctuating world market prices for the product, necessitates the need for the Australian industry to continually increase its productivity and efficiency to maintain its standing as a reliable supplier of high quality sugar.

Australia is one of the major sugar exporting nations but is only one of a number of sugar producing countries. Other significant sugar producing nations include Brazil, Argentina, Cuba and other Caribbean Islands, Thailand, India, Southern Africa, and United States of America.

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.5 5 *555 0@ 0* S 0* 0 555 o S 0 55 3 Regardless of the country of origin of sugar produced from sugar cane, the production of the raw sugar follows a basic universal procedure.

Sugar cane is grown in the field. When ripe, the sugar cane plants are harvested, utilising a variety of methods. In more technologically advanced countries like Australia, the sugar cane is harvested by mechanical harvesters which cut the cane plants off at the ground and feed the cane stalks through knives, producing billets of sugar cane cane cut into pieces) which are then transported utilising a variety of machinery.

In less technologically advanced countries, manual labour is employed to harvest the sugar cane.

Regardless of the technological advancement of the different sugar cane producing nations, the sugar cane is processed in sugar mills which are often situated long distances from the sugar cane fields. The harvested cane is transported to the sugar mills using a great variety of transportation S 15 systems.

:Once at the mill, the cane is subjected to processes whereby the cane is crushed to release the juice which is then further processed to produce S" sugar crystals.

discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia before the priority date of each claim of S: 25 this application.

*.*Summary of the Invention Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

According to a first aspect, the present invention is an apparatus for extracting sugar-containing juice from sugar-containing plant matter, the apparatus comprising: an inlet means for receiving the plant matter; 3a a comminuting means for finely comminuting the received plant matter; and a separating means for separating the sugar-containing juice from the finely comminuted plant matter.

According to a second aspect, the present invention consists in a process of extracting sugar-containing juice from sugar-containing plant matter using an apparatus having at least an inlet means for receiving the plant matter, a comminuting means for finely comminuting the received plant matter, and a separating means for separating the sugar-containing juice from the finely comminuted plant matter, the process comprising the steps of: feeding the plant matter to the inlet means; i o *o*o* go o *o *0

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0 5.@ finely comminuting the plant matter by passing it through the comminuting means; and separating the sugar-containing juice from the plant matter in the separating means.

The present invention will facilitate the extraction of sugar cane juice in the field, as opposed to the concept of milling processes being performed in centralised milling facilities. The invention in another design will facilitate the extraction of raw sugar in the field. The invention in another design will facilitate the extraction of any, or all, either individually, or in any combination, or state, of the components of a juice bearing sugar cane, sugar beet or other sugar/saccharin containing bamboos, grasses or vegetable.

The invention can be of any shape and be made of any material, and utilise any appropriate technology. The invention can be applied or manufactured as an independent processing unit or as part of a combined 15 harvesting processing train or as part of an integrated harvester.

The invention can be modified in various and numerous ways to be utilised to extract the juice of other juiceable products.

The advantages of such a system are manifold. Currently, sugar cane harvesting methods result in the removal of much and in some cases all of 20 the sugar cane crop from the field. This loss of biomass must be compensated for by the application of fertiliser to the fields to maintain crop production levels. The fibre remaining from the crushing process is either used by the mill as fuel to run boilers or sold by the mill as stockfeed or fertiliser, or used in the production of building material. The farmer gains 25 nominal direct commercial advantage from the remaining fibre.

The invention allows the fibre remaining after the in-field processing of the sugar cane to be returned to the field as fertiliser or to be used in what ever way the farmer desires. In effect, the in-field processor results in only the sugar cane juice being removed from the field with all other elements of 30 the sugar cane crop being left in the field to be used by the farmer for what ever purpose he sees fit.

Coupled with the practice of green cane harvesting which has been trialed in most Australian cane growing districts and is increasing in application, the returning of cane fibrous material to the field could well lead to a decrease in the requirement for application of artificial fertilisers to the fields to maintain crop yield levels.

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0*S@ .0 S 0@eO Oe The invention allows the farmer to gain the maximum benefits from his sugar cane production.

The invention also leads to a significant reduction in the volume of product which needs to be transported to the sugar mill. Sugar cane juice accounts for the largest percentage of the total mass of the sugar cane crop, therefore the change of mass will depend on the amount of fibre left in the field. Thus, the reduced volume of material which needs to be to transported away from the farm has the potential to result in reduced transport costs, which in turn leads to increased financial return to the producers. Likewise, the invention of the in-field processor and the production of juice in the field eliminates the need for sugar mills to possess large crushing plant which requires appreciable amounts of capital investment, energy and maintenance, thereby allowing for an incremental expansion compared to a current large mill upgrade or new construction. Therefore the potential financial 15 advantage for the milling sector of the industry is also substantial once these factors are taken into consideration.

Another benefit of the invention is the reduced infrastructure requirement needed in expansion of existing cane growing areas or the development of new growing areas.

20 Because of the envisaged increased return to growers, it may be feasible in the future to develop new growing areas dedicated to the production of ethanol. The idea of ethanol being produced from sugar cane is not a new concept, and is a product of the Plane Creek sugar mill in the Mackay region of Queensland. More than a decade ago, much discussion centred around this proposal. However, the large scale production of ethanol from sugar cane never eventuated because the farmer could not be guaranteed the same price for his cane as that received by him for cane used to produce sugar. Ethanol is considered a clean fuel compared to common fuels in use today. With Australia coming under increasing pressure to reduce greenhouse gas emissions, the use of ethanol as opposed to other traditional fuels could be seen as a positive, environmentally friendly step by the Australian nation. In fact, the use of ethanol as a fuel to drive the sugar mill is possibly a more environmentally responsible process than the burning of bagasse.

Yet another advantage of the invention is the reduction in air pollution caused by sugar mills. Presently, sugar mills add water to the bagasse 0 a.

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a S 0 a S *o 0 0 0 0060 0 ao 0000 o oooo o@ o 0 0 0 00 0 00 00 0 00 0W 000 derived from the crushing of the sugar cane to aid in the recovery of the available sugar. The in-field processor results in the supply of undiluted sugar cane juice to the sugar mill. This juice is suitable for processing, requiring no addition of water. In effect, such a system will reduce water usage in the mill and result in less air pollution from the mill due to the fact that less water needs to be driven off the juice.

This invention has the potential to significantly reduce the negative environmental effects associated with the need of the industry to dispose of large quantities of centrally located surplus fibrous matter.

EQUIPMENT DESIGN AND OPERATION Overview The present invention covers all the possible variations and permutations for separating all the constituent parts of a juice containing 15 product in the field where the useable products, either in part or fully or a combination of such, are extracted and dispatched to further processing facilities or final market and the other parts returned to the field either alone or with other field treatment products, for example fertilisers or chemical or biological control agents, after the required parts are extracted.

The harvested cane is delivered to the in-field processor directly from the harvester to the inbuilt processor or to a separate processor operating in tandem with the harvester or delivered to the separately located processor by cane transporters or other transport method such as a conveyor, working in conjunction with the harvester where the cane would then pass through, for 25 example, the following process.

The in field processor design in one form would contain a series of cutting blades/knives/disks, in another form a series of chopper knives, in another form contain a shredding device, in another form a crusher (either ball or roller or any other crushing method), in another form a combination 30 of any or all of the previously mentioned methods or any other method for reducing the juice containing medium to a size consistent with efficient juice extraction and consistent with efficient rupturing of the plant cell wall to release the juice.

The ruptured cells would be processed to remove the juices by, in one embodiment, a series of squeezing rollers, in another embodiment, a belt press, in another embodiment, a centrifuge, in another embodiment, 00 0 06 04 0 a a.

0 4 *4 chemical extraction or in any other method or combination of methods of separating the juice from the cells.

The in-field processor in one embodiment would be inbuilt with a harvester, in another form be interconnected with the cane harvester, in another form be a stand alone machine operating directly from or adjacent to the harvester, in another form be a stand alone machine in which the cane is transported and the juice extracted. The extracted juice is then transported to the mill for processing or even to an in-field processing plant.

The in field processor in one embodiment would return all the products of the harvesting to the field and extract only the juices, sugar or sucrose juices.

The in-field processor in another embodiment would allow the harvestable juicable products to be separated into their various components and the separate components, either alone or in combination, be selected for 15 further processing or returned to the field. The bagasse may be delivered to a Maceration bath or subjected to Imbibition where residual sugars are absorbed into the liquid prior to recompression and finally returned to the field. This level of processing may occur on the in-field machine or be a stand alone treatment and may or may not be included in the final process 20 depending on the economic advantage of such additional treatment compared to the quantities of diluted juice recovered and the additional cost of water removal to obtain the recovered sugars. The undiluted juice is able to be kept separate in this design. The example has not included Imbibition or Maceration processing.

25 The in-field processor in another embodiment could also process the juices to their final constituent components. In one form it would produce for example, sugar crystals, molasses or other marketable products in the one machine. In another form the juice would be extracted in one machine and the further processing of the juice to produce for example, sugar crystals, 30 molasses or other marketable products would be performed in a separate infield located machine.

One Preferred Embodiment of the Invention In this example, only the main processing componentry has been described. In this example a processor interconnected to a current style harvester is used as an example only, as this enables the application of the invention to be demonstrated. Standard engineering applications, such as for 40C4 64 00 S 04b* 4 S. S 0* *0o 0O S 0O S SO ~1O4 OL1O4 C~i,

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*0 a 4U .600 .6 0 00 00 005 example, machine body, drive trains, hydraulics, electrics, pumping systems, feed systems, controls, control circuits, piping, fibres, etc have not been detailed as it is the process and the general design of a machine that can comply with the objectives of the invention that is critical.

This example is described with reference to the accompanying drawings of a sugar cane in-field processor, the drawings comprising: a process flow diagram; plan, side elevation and cross-section views; and a pictorial view of the processor.

The cane is delivered to the in-field processor either directly from the harvester where it is fed into the cutting stack, or if transported to the in-field processor either operating in tandem with the harvester, where possibly it could have been directly fed into the cutting stack if appropriate, or in the case of a separate located in-field processor then the cane is loaded into a 15 receiving bin and a feeder system delivers the cane to the cutting disk. In this application washing or other pre-treatment, of any nature or form of the cane may prove to be appropriate before processing commences. In fact the washing or other pretreatment may be incorporated into all designs of processor be they stand alone or integrated with the harvesting operation.

The cane is delivered by any appropriate method to ihe commencement of the cutter stack.

1. Cutter In the example drawing, the cane is fed into the top of the cutter, where a feeder disk steadily rotating at a selected rate ensures the cane 25 billets are pressed against the first cutter disk or blade assembly. The cutter disk will rotate in the opposite direction, or same direction whichever is found to be the most efficient direction for any reason, and possibly at a higher revolution, with actual speed varying depending on the various design factors. The cutter disk will cut the 30 cane into small pieces which will be delivered to the next feeder disk which will ensure the cane billets are pressed against the next cutting disk and the containing area is cleared of part processed cane and so on until the cane is reduced to size where most of the juice containing cells are ruptured. The actual number of feeder and cutting disks will vary depending on cane conditions and equipment design, i.e. speed of cutter disk rotation, cutter blade design and number etc. The .00. a o O 66 S 60 15 9 or Ace.

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second or subsequent feeder disk may be replaced by a counter rotating cutter disk if proved to be the better option.

The cut or prepared fibre and juice falls into or is delivered by any other means to the processor/pulp chamber area.

2. Processor/Pulp Chamber The cut or prepared fibre and juice collects in this area where a series of high speed rotating cutter blades endeavours to ensure the "pulp mass" is finely cut with the aim of facilitating further cell wall cutting or rupturing. It is expected that during the process the area would become filled with juice and produce a liquid/slurry in which the processor blades would chop the cane to a fine constituency.

As the "pulp mass" becomes saturated with fibres, some float and are further processed by the high speed cutter blades, which the other fibres settle to some extent. Fibre is removed from the area by the screw extractor.

3. Screw Extractor The screw extractor would lift the cane fibres from the "pulp mass" in the process allowing the excess juice to run back into the storage area. The pulp fibres would discharge from the top of the screw extractor into the roller feeder. The excess juice would remain in the storage area until the liquid level reaches a position where the time taken to extract the fibre is too short to allow the excess juice to run back to the pulp chamber area. As the level of juice rises in the pulp chamber, excess juice would then carry over with the extracted fibre to the roller feeder screw.

4. Roller feeder The extracted fibre and juice is transferred to the juice extraction rollers and in the process concentrated and compressed in such a manner as to ensure feed into the pressure rollers. In this process juice is initially squeezed out, or is excess juice, and the juice runs to the juice/pulp chamber.

.:30 Juice extraction rollers The series of rollers extract the juice from the bagasse, while shredders break up the compressed bagasse prior to selected compression rollers.

The extracted juice runs into the juice/pulp chamber.

6. Juice/pulp chamber The chamber contains the extracted undiluted juice with some carry over fibre and other residual matter.

7&8. Compressed bagasse shredder and discharge screw After the juice has been extracted, the bagasse is, on discharge from the last series of juice extraction rollers, fed into a shredding device.

*The shredded bagasse is then conveyed by the discharge screw where oooo fertilisers, or chemicals could be added if required, or they could be 15 added later as a separate discharge, to the end of the in-field processor when operating as part of the mobile harvesting machine or tandem S.machines, feeding them back on to the field. If operating as a stationary unit then the bagasse, either shredded or compressed, is discharged to an appropriate disposal method, or sold on as required or appropriate. The bagasse shredder may not need to be used if S .supplying bagasse to the mill or cattle/fertiliser feedstock etc. due to the smaller volume of material requiring transport. If discharged for further processing not directly returned to the field), the bagasse is discharged by conveyor to the receiving transport or storage operation.

9. Primary juice centrifuge A centrifuge drawing from the juice/pulp chamber extracts the fibre and other residual matter from the undiluted juice, and returns the fibre etc to the processor/storage area for reprocessing and eventual discharge with the bagasse.

Juice storage The undiluted juice from the centrifuge is discharged into the on-board juice tank where it is regularly transferred to a main storage tanker for transport to a mill for further processing or to an in-field mill for processing. The discharge could be as and when the tank becomes full or by a continuous umbilical permanently or regularly connecting the processor to in-field storage or processing plant or for example the existing centralised milling facility.

11. Power back Any method and size of power pack required to drive the machinery.

Although the example described above details cutting disks, processor, juice extraction rollers and screw conveyors, the actual combination of equipment that could be utilised to achieve the objectives of the invention is many and varied. The cutting disks could be replaced by chopper blades or ball rollers or a combination of both or any method for rupturing the juice oooo containing cells. The processor may by superfluous if the cutting disks 15 perform the function highly efficiently, or they may become the primary means of rupturing the cells after the cutter disks have roughly cut the cane to a manageable size. This process may well be performed by appropriate homogenisation technology. The juice extracting rollers may be replaced by a belt press or a centrifuge or centrifuges, or a combination of rollers and centrifuge or even ball rollers. The method of fibre extraction may be replaced by delivering the ruptured fibres directly to a centrifuge. The methods of achieving the aim of the invention are many and varied.

The above description details a method of extracting the juice. The juice can then be clarified, filtered, strained and the resultant liquid converted into raw sugar by, for example, an integrated, or stand alone unit, vacuum microwave heating system to remove the water component of the liquid. The raw sugar can then be centrifuged to remove the molasses component as required. The components, either individually, or with any combination or at any stage of the in field process, as required, can be delivered to either a mill for separation, or to a refinery for turning into granulated sugar, brown sugars, syrups etc.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims (27)

1. An apparatus for extracting sugar-containing juice from sugar- containing plant matter, the apparatus comprising: an inlet means for receiving the plant matter; a comminuting means for finely comminuting the received plant matter; and a separating means for separating the sugar-containing juice from the finely comminuted plant matter, wherein the comminuting means comprises a feeding means for feeding plant matter from the inlet means into a cutter means, the feeding means comprising at least one rotatable feeding disk and the cutter means comprising a plurality of cutting disks mounted to a substantially vertical and rotatable drive shaft, at least one of said feeding disks being positioned above an uppermost one of said plurality of cutting disks.

2. The apparatus of claim 1 wherein at least one of the cutting disks is adapted to rotate in an opposite direction to that of the other cutting disks.

3. The apparatus of claim 1 wherein at least one feeding disk is disposed "above each of the cutting disks of the comminuting means.

4. The apparatus of claim 3 wherein said at least one feeding disk rotates in an opposite direction to that of at least one of its adjacent cutting disks.

5. The apparatus of claim 1 wherein the comminuting means is disposed in a first chamber having the inlet means at an upper end thereof such that :.the finely comminuted plant matter is adapted to fall into the chamber.

6. The apparatus of claim 5 wherein the chamber comprises at least one further cutter means disposed adjacent its lower end and adapted to further comminute the plant matter once it is in the chamber.

7. The apparatus of claims 5 wherein an extraction means is adapted to extract the finely comminuted plant matter from the first chamber and transport it to the separating means.

8. The apparatus of claim 7 wherein the extraction means comprises a screw extractor.

9. The apparatus of claim 1 wherein the separating means comprises a centrifuge.

The apparatus of claim 1 wherein the separating means comprises a series of rollers for pressing the comminuted plant matter passed therethrough.

11. The apparatus of claim 1 wherein the separating means comprises a chemical separating process.

12. The apparatus of claim 1 wherein the separating means comprises a roller feeding device that feeds the finely comminuted plant matter into the separating means, a plurality of extraction rollers that extract sugar- containing juice from the plant matter, a chamber for storing at least the extracted sugar-containing juice, and a centrifuge for further processing of the juice.

13. The apparatus of claim 12 wherein the centrifuge has an outlet for the separated sugar-containing juice and an outlet for any plant matter that enters the centrifuge.

14. The apparatus of claim 13 wherein the outlet for the plant matter feeds the plant matter back to the first chamber.

The apparatus of claim 13 wherein the outlet for the juice is in fluid S: 15 communication with a storage container for the juice.

16. The apparatus of claim 12 wherein the separating means further comprises a shredding means for shredding the plant matter that has passed through the extraction rollers, and at least one further set of extraction rollers.

17. The apparatus of claim 16 further comprising a plant matter extraction means downstream of the separation means.

18. The apparatus of claim 17 wherein the plant matter extraction means comprises a screw extractor.

19. The apparatus of claim 1 wherein the apparatus comprises part of a U harvester for the plant matter. 25

20. The apparatus of claim 19 wherein the harvester is a sugar cane harvester.

The apparatus of claim 1 wherein the apparatus further comprises an apparatus for extracting raw sugar from the separated sugar-containing juice.

22. A process of extracting sugar-containing juice from sugar-containing plant matter using an apparatus as defined in any one of the preceding claims, the process comprising the steps of: feeding the plant matter to the inlet means; finely comminuting the plant matter by passing it through the comminuting means; and separating the sugar-containing juice from the plant matter in the separating means. 14

23. The process of claim 22 wherein the step of separating the juice from the finely comminuted plant matter comprises passing the plant matter through at least a series of rollers, a centrifuge, and/or a chemical process.

24. The process of claim 22 wherein the plant matter is sugar cane and the process comprises the steps of firstly harvesting the cane and cutting it into billets before undergoing the step of fine comminution.

The process of claim 24 wherein the process is performed at the site of harvesting of the sugar cane.

26. The process of claim 25 wherein the plant matter is discharged from the apparatus back to the site of harvesting after the juice is separated therefrom.

27. The process of claim 22 wherein the juice undergoes further processing to extract raw sugar therefrom. a a *oo .i a o go* o